The time of off-peak charging is usually seven hours between midnight and 7.00am GMT, and this is designed to power storage heaters and immersion heaters.
The use of live dynamic pricing is not limited in case of low difference between peak- and off-peak demand, unavailability of adequate time-of-use metering.
In general, evening service arrives every 15 minutes, off-peak service arrives at 10-minute intervals, and at peak hours trains come every six minutes.